More on this Topic

For those who doubt that the global climate is changing, seven new graphs should put that notion to rest. This morning the Intergovernmental Panel on Climate Change (IPCC) released the first public summary of a six-year study called Climate Change 2013: The Physical Science Basis. It contains the report’s graphs and explains the data behind them. As a set, the graphs show strong trends over many decades: Average surface temperatures have risen up to 2.5 degrees Celsius in numerous places around the world, global sea level is has risen 20 centimeters, Arctic summer sea ice has shrunk by 4 million square kilometers, and so on.

During a press conference held to release the details, Thomas Stocker from the University of Bern in Switzerland and co-chair of the working group that wrote the report, said climate change is the greatest challenge of our time, adding: “It threatens our planet, our only home.” United Nations Secretary General Ban-ki Moon, appearing by Internet video at the press conference, said, "The heat is on. Now we must act." The U.N. convened the IPCC in 1988 to assess the state of the planet’s climate and the extent to which human actions are altering it. More than 600 scientist authors from 39 countries assessed some 9,000 peer reviewed studies and 54,000 comments to generate this latest report.